678 GEOLOGICAL SURVEY OF THE TERRITORIES. 
vol. 11, . 190), “In the common Fowl each carotid * * * enters (ing) 
the canal formed by the hypapophyses.” 
In the completed twelfth vertebra of mature birds we find this 
hypapophysis very large, with expanded extremity, and the parapophy- 
sis, on either side, sending down long subsquamous processes. In the 
thirteenth segment of the “ bird of the year” the parapophyses begin to 
take onachange. This change develops in the adult still a perfect hypa- 
pophysis, but in the younger individual the parapophysial element 
begins to be notched anteriorly, a part favoring the pleurapophysis, a 
part the centrum, so that in the fourteenth vertebra of the adult the 
hypapophysis is still present anteriorly with a tubercle developing on 
either side of it, with the parietes of the vertebral canal very much 
slenderer. In examining this segment in the younger bird we ascertain 
that the original ossicle is now a descending pleurapophysis meeting 
the parapophysis, a delicate and independent process, which, in the fif- 
teenth and last cervical vertebra, constitutes a free rib, while the hypapo- 
physis consists of a mid-process and a smaller nodule on either side. 
This beautiful metamorphosis can be thoroughly studied and easily com- 
prehended in the cervical portion of the vertebral column in our Cathar- 
tes aura. 
So that, as a partial recapitulation of the first fifteen segments, we 
find that they make up the “cervical portion” of the column. ‘Their cen- 
tra are universally subcompressed at their middles, they develop in the 
young bird parapophysial projections that eventually produce free ribs 
by the aid of the descending pleurapophyses, and their interarticula- 
tions, as far as their bodies are concerned, bear out the general ornithic 
law of being apparently procelous on vertical section and opisthoce- 
lous on horizontal section. . 
Backwards from the fifteenth the vertebral segments or the links of 
the chain take on a metamorphosis that is characteristic of the Tetraon- 
ide. It consists in, in all the adults of the genera, a consolidation ot 
the ensuing four vertebre. The confluent bone thus formed constitutes 
the major part of the dorsal division of the spinal column and invariably 
supports free pleurapophyses (Plate VI, Fig. 55, Centrocercus, ad. 3). 
In Centrocercus these four vertebre can easily be distinguished from 
each other until the bird is over a year old, but very soon after this all 
sutural traces are entirely obliterated and we have the segment as rep- 
resented in the plate. 4 
The neural spines become one long parallelogrammic plate, occasion- 
ally exhibiting a for- 
amen or so at the 
site of the original 
interspinous spaces. 
Its crest is round- 
ed, but has no inde- 
pendent rim. Mus- 
cular fascia attached 
toit posteriorly often 
SAM ossifies, leaving in 
Pediccetes phasianellus. the prepared skele- 
ton flattened spiculz, on either side, directed backwards. The anterior 
aspect of this bone has all the necessary elements to meet the last free 
vertebra beyond it. The first pair of diapophyses are the shortest, the 
last pair the longest and most raised; these processes are more or less 
bound together by metapophysial offshoots of variously defined serrate 
margins, that allow interdiapophysial vacuities to exist. Below, and 
